The present invention relates to an electronic device and a control method for the electronic device and, more particularly, to a technique for detecting the voltages of component units of a portable electronically controlled timepiece incorporating a power generating unit.
In recent years, small electronic timepieces of a wristwatch type or the like have been implemented that include power generating units, such as solar batteries, so as to obviate the need for replacing batteries. These electronic timepieces are provided with features for temporarily storing electric power, which has been generated by the power generating units, in large-capacitance capacitors or the like. When power generation is not being carried out, time display is performed using the electric power discharged from the capacitor. This feature enables stable operation for an extended period of time without batteries. From the standpoint of cumbersome replacement of batteries or the issue of disposal of the batteries, many electronic timepieces are expected to carry built-in power generating units in the future.
Such an electronic timepiece with a built-in power generating unit is provided with a voltage detecting circuit for detecting a supply voltage in order to prevent the supply voltage of a power unit, which is applied to a time display circuit, from exceeding a breakdown voltage level of the time display circuit, or to carry out various types of control.
An operation of the voltage detecting circuit becomes unstable and a detection error may result if the supply voltage drops below a predetermined operating voltage of the voltage detecting circuit.
A detection error of the voltage detecting circuit may lead to a malfunction of a subsequent control system, resulting in unstable operation of the entire system.
Accordingly, an object of the present invention is to provide an electronic device and a control method for the electronic device that allow prevention of detection errors of a voltage detecting circuit of the electronic device, thereby ensuring stable operation of the entire system.
According to a first aspect of the present invention, there is provided a portable electronic device comprising: a power generating unit for generating electric power by converting first energy into second energy, namely, electrical energy; a power unit for storing electrical energy obtained by power generation; a driven unit driven by the electrical energy supplied from the power unit; a power generation detecting unit for detecting whether the power generating unit is generating storable electric power that is sufficient to be stored in the power unit; a stored power voltage detecting unit for detecting a stored power voltage of the power unit; an operating voltage detecting unit for detecting whether the stored power voltage of the power unit has reduced to an operating voltage of the stored power voltage detecting unit or less; and a voltage detection control unit for prohibiting an operation of the stored power voltage detecting unit based on detection results of the operating voltage detecting unit and the power generation detecting unit if the stored power voltage of the power unit has dropped to the operating voltage or less and the generation of storable power is not being carried out.
According to a second aspect of the present invention, there is provided a portable electronic device comprising: an oscillating unit for outputting an oscillation signal having a predetermined frequency; a clock generating unit for generating and issuing a predetermined clock signal based on the oscillation signal; a power generating unit for generating electric power by converting first energy into second energy, namely, electrical energy; a power unit for storing electrical energy obtained by power generation; a driven unit driven by the electrical energy supplied from the power unit; a step-up/down unit for increasing or decreasing a voltage of the electrical energy obtained by power generation based on the clock signal, then supplying the voltage to be stored in the power unit; an oscillation state detecting unit for detecting whether the oscillation unit is at rest; a power generation detecting unit for detecting whether the power generating unit is generating storable electric power that is sufficient to be stored in the power unit; a stored power voltage detecting unit for detecting a stored power voltage of the power unit; and a voltage detection control unit for prohibiting an operation of the stored power voltage detecting unit based on detection results of the oscillation state detecting unit and the power generation detecting unit if the oscillation unit is at rest and the generation of storable power is not being performed, while allowing the stored power voltage detecting unit to operate if the oscillation unit is at rest and storable power is being generated.
According to a third aspect of the present invention, in the first or second aspect of the present invention, the voltage detecting control unit decides that no storable power is being generated unless generation of storable power is continuously detected for a predetermined specified time or more by the power generation detecting unit.
According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the voltage detection control unit decides that no storable power is being generated unless a total time per preset unit time of a time during which the storable power generation is detected by the power generation detecting unit exceeds a preset reference total time.
According to a fifth aspect of the present invention, in the second aspect of the present invention, the power unit comprises a first power unit for storing electrical energy obtained by power generation, and a second power unit for storing electrical energy obtained after the step-up/down unit increases or decreases a voltage of the electrical energy stored in the first power unit, and the stored power voltage detecting unit comprises a first stored power voltage detecting unit for detecting a stored power voltage of the first power unit and a second stored power voltage detecting unit for detecting a stored power voltage of the second power unit.
According to a sixth aspect of the present invention, in the first or second aspect of the present invention, the voltage detection control unit causes the stored power voltage detecting unit to intermittently perform a detecting operation when the stored power voltage detecting unit is in an operable state.
According to a seventh aspect of the present invention, in the first or second aspect of the present invention, the driven unit has a time measuring unit for display time.
According to an eighth aspect of the present invention, in the first or second aspect of the present invention, the voltage detection control unit comprises a timer unit that starts measuring a duration of the generation of storable power when the power generation detecting unit detects that the generation of storable power sufficient to be stored at the power unit is being performed, and resets the measured duration when the power generation detecting unit detects that the generation of storable power is not being performed, and the voltage detection control unit decides that storable power is being generated when the duration reaches a predetermined specified time or more.
According to a ninth aspect of the present invention, in the first or second aspect of the present invention, the voltage detection control unit comprises a timer unit that adds up power generation detection times during a period in which the power generation detecting unit detects that the generation of power sufficient to be stored in the power unit is being performed, and resets a total value of the power generation detection times at every predetermined specified unit time, and the voltage detection control unit decides that the generation of storable power has been detected only when a total time per unit time of the time in which the generation of storable power is detected exceeds a predetermined specified time (reference total time).
According to a tenth aspect of the present invention, there is provided control for a portable electronic device comprising a power generating unit for generating electric power by converting first energy into second energy, namely, electrical energy, a power unit for storing electrical energy obtained by power generation, and a driven unit driven by the electrical energy supplied from the power unit, the control comprising: a power generation detecting step for detecting whether the power generating unit is generating storable electric power that is sufficient to be stored in the power unit; a stored power voltage detecting step for detecting a stored power voltage of the power unit; an operating voltage detecting step for detecting whether the stored power voltage of the power unit has reduced to an operating voltage of the stored power voltage detecting unit or less; and a voltage detection control step for prohibiting an operation of the stored power voltage detecting unit based on detection results of the operating voltage detecting step and the power generation detecting step if the stored power voltage of the power unit has dropped to the operating voltage or less and the generation of storable power is not being carried out.
According to an eleventh aspect of the present invention, there is provided a control method for a portable electronic device comprising an oscillating unit for outputting an oscillation signal having a predetermined frequency, a clock generating unit for generating and issuing a predetermined clock signal based on the oscillation signal, a power generating unit for generating electric power by converting first energy into second energy, namely, electrical energy, a power unit for storing electrical energy, a driven unit driven by the electrical energy supplied from the power unit, and a step-up/down unit for increasing or decreasing a voltage of the electrical energy obtained by power generation based on the clock signal, then supplying the voltage to be stored in the power unit, the control method comprising: an oscillation state detecting step for detecting whether the oscillation unit is at rest; a power generation detecting step for detecting whether the power generating unit is generating storable electric power that is sufficient to be stored in the power unit; a stored power voltage detecting step for detecting a stored power voltage of the power unit; and a voltage detection control step for prohibiting a stored power voltage detecting operation in the stored power voltage detecting step based on detection results of the oscillation state detecting step and the power generation detecting step if the oscillation unit is at rest and the generation of storable power is not being performed, while allowing the stored power voltage detecting operation in the stored power voltage detecting step to be performed if the oscillation unit is at rest and storable power is being generated.
According to a twelfth aspect of the present invention, in the tenth or eleventh aspect of the present invention, the driven unit has a time measuring unit for displaying time.